High Energy Laser Testbed for Accurate Beam Pointing Control

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algorithms are implemented in the computer simulation. NFOV video tracker simulations were conducted with three disturbance sources. The first two were from mechanical vibration, one at 20 Hz and another at 50 Hz. The third disturbance was a 0.5 Hz sinusoidal in addition to broadband white noise. This was to simulate the effects of a target motion. Only the PI controller was active <strong>for</strong> the first two seconds of all simulations. A comparison of FX-LMS and FX- RLS per<strong>for</strong>mance is shown in Figures 16 through 17. The frequency analysis shown in Figures 16 and 17 was conducted on the steady state period of 9-12 seconds. As expected, there is a significant reduction in target pointing error once the adaptive filter is engaged. Both LMS and RLS algorithms reduced RMS target error to less than one quarter of that produced by the PI controller alone. While the FX-RLS algorithm produces lower steady state error, it has the drawback of significant transient errors. The FX-LMS algorithm is much slower to converge as demonstrated by the significant error spike seen through ten seconds of simulation. Further indication that FX-LMS is slower to converge can be seen in Figure 18, which illustrates the convergence of FX-LMS and FX-RLS weights. After ten seconds, FX-RLS weights have stabilized, while FX-LMS weights continue to change. Figure 16. Target error using NFOV FX-LMS controller Proc. of SPIE Vol. 7587 75870G-12 Downloaded from SPIE Digital Library on 31 Jul 2012 to 205.155.65.56. Terms of Use: http://spiedl.org/terms
Figure 17. Target error using NFOV FX-RLS controller Figure 18. NFOV Video tracking adaptive filter weights comparison Proc. of SPIE Vol. 7587 75870G-13 Downloaded from SPIE Digital Library on 31 Jul 2012 to 205.155.65.56. Terms of Use: http://spiedl.org/terms
Page 1 and 2: High Energy Laser Testbed for Accur
Page 3 and 4: capability to monitor analog input
Page 5 and 6: 2.2.2 Narrow Field-of-View (NFOV) V
Page 7 and 8: Figure 8. Elevation Axis Transfer F
Page 9 and 10: 2.3.5 NFOV Control Bandwidth A swee
Page 11: For adaptive filters, the reference
Page 15 and 16: Figure 20. Jitter Control Simulatio
Page 17 and 18: Figure 24. Frequency Domain NFOV tr
Page 19: adaptive controllers with multiple

High Energy Laser Testbed for Accurate Beam Pointing Control

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